The present invention relates to a trigger-type liquid dispenser.
A conventional trigger-type liquid dispenser 1 shown in FIG. 12 comprises a mounting sleeve 2, a vertical sleeve 2a, an ejecting sleeve 3, a cylinder 4, a trigger 5, a plunger 6, a nozzle fitting sleeve 7 and a nozzle head 8. The vertical sleeve 2a is erected from an upper portion of the mounting sleeve 2 to be fitted onto an outer surface of a neck portion of a container body (not shown in FIG. 12). The ejecting sleeve 3 is projected forwardly from an upper end of said vertical sleeve 2a. The trigger 5 is swingably attached to a front portion 30 of said ejecting sleeve 3. The cylinder 4 is projected forwardly from said vertical sleeve 2a. The plunger 6 is arranged in a cylinder 4 and urged forwardly. A front end of the plunger 6 is engaged with a rear surface of an upper portion of said trigger 5. The nozzle head 8 is fitted into a front end of the ejecting sleeve 3 via the nozzle fitting sleeve 7. The nozzle head 8 has a nozzle hole 10. Liquid stored in the cylinder 4 is ejected through the nozzle hole 10 of the nozzle head 8 by pulling the trigger 5. When the trigger 5 is released, the plunger 6 is moved or returned forwardly, thereby returning the trigger 5 to its initial position, so as to suck up the liquid within the container body into the cylinder 4. Numeral 27 designates a cover plate which blocks the front surface of the nozzle head 8 openably.
In said trigger-type liquid dispenser, since liquid is ejected even if the trigger 5 is pulled inadvertently, a liquid discharge passage 11 in the nozzle head 8 and the nozzle fitting sleeve 7 fitted into the front end of the ejecting sleeve 3 is divided into a front portion 11b and a rear portion 11a. When the nozzle head 8 is rotated relative to the nozzle fitting sleeve 7, the nozzle head, the communication of said liquid discharge passage 11 is shut off. Liquid can be ejected only when the nozzle head is returned to its initial position.
Even if the liquid discharge passage is closed or shut by rotating the nozzle head 8 relative to the nozzle fitting sleeve 7, when the trigger 5 is pulled many times, the plunger 6 moves forwardly or backwardly a little due to the deflection or elastic restoration. Thus, high pressure liquid may accumulate in the front portion of the ejecting sleeve 3 between said discharge nozzle and the liquid discharge passage formed by said nozzle fitting sleeve 7 due to the abnormal high pressure in the cylinder. In this condition, when said nozzle head 8 is rotated to open the liquid discharge passage, high pressure liquid accumulated in the front portion of the ejecting sleeve 3 may happen to be discharged through the nozzle hole without operating the trigger 5. There is also the danger that the nozzle head 8 may be disconnected due to high pressure in the ejecting sleeve 3 when the trigger 5 is pulled strongly.